1. Field of the Invention
This invention relates to methods of using hydrocarbon product wells producing both a hydrocarbon product and brackish water or brine, and the use of these wells as a water source, as well as to apparatus for desalinating water that include hydrocarbon product wells producing brackish water or brine.
2. State of the Art
Hydrocarbon product wells produce oil, gas and sometimes other alternative products, for example, brackish water or brine. Usually the alternative products are thought of as being of no value at all. The well can be active and coproduce the hydrocarbon products and the alternative products, or it can be inactive, many times because the well over produced the alternative coproduct.
When a hydrocarbon product well ceases to produce oil or gas, either because the well runs dry or because it starts to produce large amounts of some less desired alternative product, for example, brackish water or brine, the well is inactivated. First, the hole is plugged temporarily by closing its valves, but the well must be physically blocked with concrete or the like to permanently plug it. Then, if a well site is to be abandoned, whatever superstructure that might exist must be removed from the site. In the case of inactivating all the hydrocarbon product wells on off-shore oil platforms, the process is particularly expensive. As on land, each of the wells must be plugged. However, the entire superstructure of the platform must be removed from its moorings on the sea floor and the platform removed from the site as a potential hazard to navigation. Inactivating is an expected occurrence in the life of a hydrocarbon product well, but it is expensive and removes a potential resource, particularly if the well is producing an alternative product.
Brackish water, one alternative product associated with many hydrocarbon product wells, is normally thought to be of little value, because, although it is not as salty as sea water, it is too salty to be used for either human consumption or agriculture. However, many hydrocarbon product wells are located in arid or semi-arid locales where potable water can be an extremely valuable resource. In California, one such semi-arid locale, the increasing population has an ever increasing need for water. However, parts of California have suffered from severe drought, and may continue to suffer from drought, straining the available water resources so much that many local governments in California plan to build desalination facilities to desalinate sea water, despite the expense.
Not all sources of brackish water or brine are considered suitable for creation of potable water, that is, water for human consumption. In some instances the source of water is considered unsuitable even for agricultural use. Municipal waste water is an example of a source of water not considered suitable for human consumption. In some areas of the country it is treated for reuse, but not for human consumption.
For most purposes, the most widely used methods of desalinating salt water are distillation and reverse osmosis. An overview of reverse osmosis technology is found in The Handbook of Industrial Membrane Technology. Mark Porter editor, Noyes Publications 1990, chapter 4, hereby incorporated by reference in its entirety. This publication discloses the implementation of reverse osmosis technology in many environments, using different feed waters, different membranes, and processing to different purities. One feed water not discussed was brackish water or brine from inactivated hydrocarbon product wells.
It would be useful if one could use the non-oil producing wells to produce potable water from the brackish water or brine that is now discarded.